Ultra-high-density silicon nanocone arrays with sharp tips by Ar + sputtering at low temperature

Abstract

Ultra-high-density silicon nanocone arrays with sharp tips have been fabricated by Ar⁺ sputtering at low temperatures. The investigation of SEM and AFM indicates that with an increasing substrate temperature from room temperature, 200 to 400°C, the density of silicon nanocone increases from 1–2 × 10⁹, 3–4 × 10⁹ to 1–2 × 10¹⁰ cm⁻², respectively. The rooter diameter of the cones decreases from 120–150 to 40–50 nm and the tip angle of cones decreases from 32–36° to 20–26°. As predicted by the Bradley–Harper theory, the ripple wavelength decreases with substrate temperature during the carbon ripple formation process, which leads to an increase in the silicon nanocone density and a decrease in the silicon nanocone rooter diameter.